We have been interested in exploiting the highly functionalized oxabicyclo[3.2.1]octadienes that are produced by the cycloaddition of furan and tetrabromocyclopropene as synthetic building blocks. As part of this program, we have prepared non-racemic derivatives of these adducts containing an α,β-dibromoenone moiety embedded in the bicyclic

It has been known for several decades that a highly functionalized family of tetrahalobicyclo[3.2.1]octadienes are readily available through the cycloaddition of furan or cyclopentadiene with either tetrachloro- or tetrabromocyclopropene. However, the application of these highly functionalized building blocks in synthesis has remained relatively unexplored in relation to their better-known counterparts derived through oxyallyl cation additions. As a first step toward utilizing these highly versatile intermediates in synthesis, a study of the addition of various nucleophiles to the halogenated nucleus has been conducted. It has been found that these halogenated systems are amenable to a wide range of functionalizations in high yields and with good selectivities.

2006 Pyran derivatives R 0340 Halogenated Oxabicyclo[3.2.1]octadiene Building Blocks: Elaboration of the Dibromoenone. -The octadiene (I) is found to be a useful synthon which can smoothly be converted into a large variety of derivatives. -(PELPHREY, P. M.; ORUGUNTY, R. S.; HELMICH, R. J.; BATTISTE, M. A.; WRIGHT*, D. L.; Eur. J. Org. Chem. 2005, 20, 4296-4303; Dep. Chem., Dartmouth Coll., Hanover, NH 03755, USA; Eng.) -Jannicke 10-149

Addition reactions of various nucleophiles to the halogenated positions of the bicyclooctene systems (I) and (IX) are investigated. The direct generation of cations with silver ion can be followed by the addition of water, alcohols and activated aromatics. Silver-promoted hydrolysis gives dihaloenones (IX), which can be substituted directly by the addition of organocopper and organomagnesium reagents. The corresponding addition products are obtained in high yields and with good selectivity. -(ORUGUNTY, R. S.; WRIGHT*, D. L.; BATTISTE, M. A.; HELMICH, R. J.; ABBOUD, K.; J.